"Air and hotel are the big-ticket items in any travel programme, but buyers who focus exclusively on those two sub-categories could be missing a trick elsewhere," he said.

In the article, expense auditing company Meridian says it queries 20 to 35 per cent of reports it processes, and says it saved ?52 (£45) in direct savings per expense claim in the first year of a contract with one client.

In the case of foreign exchange, most travellers use ATMs or an airport bureau de change which can be more costly than establishing a corporate deal on the purchase of foreign money.

In the same supplement, Cohen examines how setting up a pre-trip approvals process can achieve savings by curbing unnecessary travel. He also looks at how purchasers can make efficiencies in a category where prices remain high - car hire.